Question

# 1. a. How do you represent chemical reactions by using chemical equations? Please provide an example....

1.

a. How do you represent chemical reactions by using chemical equations? Please provide an example.

b. How do you calculate the amount of energy released/absorbed in a chemical reaction by using bond energies? Please provide an example.

c. How do you determine whether a reaction is wxpthermic or endothermic based on the sign from the process above. Please provide an example.

Ans

a) Try writing the compounds mentioned in the chemical reactions in their formula form , and place them in the equation left or right as mentioned.

For example : A reacts with B to form C and D

Equation : A + B = C + D

b) Energy is required to break the bonds and released when the bonds are formed. The net sum of these energies , form the basis of enthalpy of the reaction.

For ex, AB + C = AC + D

Suppose A-B bond energy is 100 KJ/mol

and A-C bond energy is 150 KJ/mol

So enthalpy = 150 - 100 = +50 KJ

c) Always look for the sign of enthalpy to detemine whether the reaction is exothermic or endothermic.

If the sign is positive , the reaction is endothermic , if the sign is negative , the reaction is exothermic.